The present invention relates to a spraying head as defined in the preamble of claim 1, especially for the humidification of the intake air of a piston engine, said spraying head comprising a body and a channel for the supply of a spraying medium from an inlet to at least one nozzle.
The exhaust gases of piston engines, in particular diesel engines, contain many kinds of noxious combustion products. At the high combustion temperatures, the combustion process in the cylinders of a piston engine produces nitrogen oxides (NOx), which are emitted together with the exhaust gases into the atmosphere. Because of the harmful environmental effects of nitrogen oxide emissions, efforts are undertaken to minimize their production.
As is known, adding water to the combustion process reduces the generation of nitrogen oxides. This phenomenon is based on the cooling effect of water. In practice, the introduction of water into the combustion process is often implemented by injecting water into the intake air. These arrangements are advantageous in respect of efficiency of the engine. The maximum amount of water introduced into the combustion space of the engine may be that amount which will remain in gaseous form in the intake air pressure and temperature conditions.
The object of the invention is to achieve a completely new type of spraying head that allows the intake air to be humidified in a desired manner in different engine load conditions.
Spraying head of the invention is characterized in that the spraying head is provided with at least two channels, each one which forms a separate passage to at least one nozzle.
The spraying head of the invention is additionally characterized by what is stated in claims 2–10.
The solution of the invention has numerous significant advantages. By forming several liquid feed channels in the spraying head, it will be easy to control the amount and/or quality of water to be supplied through the spraying head. By providing the spraying head with nozzles having different properties, the characteristics of the water mist to be injected can be varied in a desired manner by opening and closing the medium channels leading to different nozzles in the spraying head. Installing the spraying head as a complete module is easy as compared with mounting several separate nozzles. In addition, the aiming direction of the nozzles of the spraying head and the distances between them can be easily adjusted to the designed settings. Moreover, the spraying head can be securely mounted in the air intake duct. Using the spraying head of the invention, diverse adjustment possibilities and, when necessary, a good water distribution through the air intake duct are achieved.